This invention relates to valves and more particularly to degassing valves for use in flexible packaging.
Packages made out of flexible material are commonly used to store products to isolate the products from the ambient atmosphere. Those products may be agricultural products, foodstuffs, chemicals, etc. Typically, the flexible packages are of either a gussetted type or a "pillow" type. The gussetted type package or bag basically comprises a front and rear panel connected to each other along their respective marginal edges by gussetted side panels. The pillow or pouch-type flexible package merely consists of a front and rear panel connected to each other directly. In either case the package may be formed into a tube from a single sheet or web and then welded or otherwise seamed to complete the package.
It is a common practice to include in various types of flexible packages, whether a gussetted or pouch-type, a valve to enable air which may be trapped within the bag or gases produced by the contents of the bag to exit the bag through the valve while precluding the ambient atmosphere, e.g., air, from entering into the bag through the valve. Examples of such degassing valves are those sold by Pacific Plus, Inc., of Bellevue, Wash. SIG-Schweizerische Industrie-Besellschaft, of Heuhausen am Rheinfall, Switzerland, also sells such valves (e.g., the valve disclosed in U.S. Pat. No. 4,420,015). Wipf AG Verpackungen, of Volketswil, Switzerland, also sells such valves (e.g., the valve disclosed in U.S. Pat. No. 4,444,219). Luigi Goglio Milano, SPA, of Milan, Italy also sells such valves (e.g., the valve disclosed in U.S. Pat. No. 3,799,427, as well as other valves).
For packaging applications wherein the package is expected to be stacked on other like packages, such as on a pallet, it is of considerable importance that any entrained or entrapped air or other gases be quickly exhausted through the valve as the packages are stacked one on another to provide stability to the stack of packages. Absent the rapid egress of air or gas from the package, the stack of packages could be unstable due to air entrapped or entrained in the packages of the stack.
While the aforementioned valves of the prior art are generally suitable for their intended purposes to vent entrapped gas or air from the flexible package, they still suffer from one or more disadvantages.
For example, the heretofore identified valve sold by Pacific Plus, Inc. basically comprises a two-piece assembly in the form of a base portion in the form of a cap-like member having a rubber disk or valve member in it. The cap includes three arcuate gas exit slots which are disposed in a circular array in the center portion of the base member. A circular valve disk, such as made of neoprene or some other rubber, is disposed within the base member and over the three arcuate outlet ports. The valve is designed to flex to enable gas to flow around it and out through the exit ports when the pressure within the package exceeds the ambient pressure. The rubber disk member is held in place by three inwardly extending ears projecting inward from the base or cap member. The mounting arrangement of the disk, i.e., being held in place by the three inwardly extending ears, renders this valve susceptible to the disk popping out of place when gas vents out the valve. Such action thus renders the valve inoperative.
The heretofore identified SIG valve basically comprises a three-piece member, that is, a cup-shaped member having a central opening or port, a very thin flexible plastic disk or diaphragm, and an insert or clamping member of generally rectangular shape but having arcuate opposed ends arranged to be snap fit into the cap-shaped member to hold the flexible valve member between it and the outlet port. Gases are enabled to flow through the space between the linear sides of the clamping member and the arcuate portion of the cap under the polyester valve disk or diaphragm and out through the central opening when the pressure within the interior of the flexible package exceeds that of the ambient atmosphere. This valve is susceptible to becoming clogged or otherwise rendered inoperative in the event that the bag contains fine particulate materials which would gain ingress into the interior of the valve.
The heretofore identified Wipf valve basically comprises a three-piece member, that to is, a cup-shaped valve body having a plural holes or port, a very thin flexible plastic disk or diaphragm, and an insert or keeper of generally I-shape fit in the cap-shaped member to hold the flexible diaphragm between it and the ports. Gases are enabled to flow through the space between the sides of keeper and the arcuate portion of the cap under the diaphragm and out through the plural ports when the pressure within the interior of the flexible package exceeds that of the ambient atmosphere. This valve, like the SIG valve, is susceptible to becoming clogged or otherwise rendered inoperative in the event that the bag contains fine particulate materials which would gain ingress into the interior of the valve.
The degassing valve of Pacific Plus, Inc. also suffers from the same susceptibility to clogging or inoperative action as the SIG and Wipf valves.